Thermostat



Jan. 21, 1930. ,J GRAYSQN 1,744,465

THERMOSTAT Filed May 30, 1928 Jon n. eaayson, or mmwoon, c'A I.IFonm'A, 'ass1oNoB 'ro canteen BEA: 'coNrrnoL, nm, or mmwoon, cum-01mm, a coarom'rron or CALIFORNIA... I

'rnmmos'urr Application and Bay 30,

This invention relates to thermostats and more particularly those especially adapted to 5 ing still more particularly concerned with gas-operated devices of the kind referred to.

The thermostat of my invention is of a snap-action tlype and of an extremely simple, compact, an economical as well as durable construction, usin a normally conveXo-concave, spring meta diaphragm disk, termed a clicker disk, arranged to snap over dead center from convexo-concave to concavo-convex form and in so doing transmit movement expansion and contraction of a thermostatic element. The levers are preferably arranged to rest at their outer ends on an annular shoulder of appreciably larger-radius than the annular shoulder supporting the clicker disk,

and a plunger actuated by the thermostatic element is employed having contact with the levers near the outer ends thereof, thus re-- sulting in amplification of the movement of tlie thermostatic element. The clicker disk may be dispensed with, if desired, so that the lever or levers come into direct contact with the valve stem or other part otherwise operated by the disk, thus adapting the invention to use in an oven regulator, 1n whichcase it is evident that the flow of gas should be reguand not arranged to beturned off lated according to the temperature desired and on abruptly. v

(2) The provision of a screw adjustment in the end of the valve stem coming in contact with the clicker disk, thus permitting the es- 1928. Serial No. 281,602.

tablishment of a very finely adjusted relation between the clickerdisk and the valve for best operation, it being evident that if the valve stem were too long the gas would commence to flow slowly before the valve were thrown fully open, whereas if the valve stem were too short there would be a gradual restriction in the flow of the gas before the valve were closed.

(3) The provision of'a tubular screen fitting on an annular shoulder about the valve seat at one end thereof and at the other end in an annular groove provided in a closure plug, thus making for accessibility for cleaning, ease in assembling, and economy in construction as well as minimum restriction to flow of the gas.

The invention is fully described in the following specification in which reference is made to the accompanying drawing, where- Figure 1 is a central longitudinal section through a thermostatically controlled gas valve for a water heater made in accordance with my invention Fig. 2 is a transverse section taken on the line 2-2 of Fig. 1 looking in the direction of the arrows;

3 Fig. 3 is an enlargement of a portion of Fig. 1 showing a dotted line position of the parts to convey a better understanding of the operation of the device;

Fig. 4 is a view similar to Fig. 3 illustrating a modification of the invention intended for use with oven regulators or similar devices; and

a Fig. 5 is a View similar toFig. 1 of another modification.

'- Similar reference numerals are applied to corresponding parts throughout the views.

The dcvice of the present invention is in the nature of an improvement on that disclosed in my Patent 1,699,468, issued January 15, 1929. While the device disclosed in said patent operates efficiently and fully satisfactorily, the fact that the thermally expansible member does not expand more than a few thousandths of an inch, the expansible element being fairly short, makes it necessary to work to very close limits and, while it is coml paratively easy to produce a thermostatic valve which will snap open, it is rather difiicult to produce a valve which will snap closed unless a powerful spring is used which means a correspondingly ieavy strain on the parts. of the device. In other words, the movement of the thermally expansible member is too small to allow of much lost motion in the parts of the device. It is, therefore, an important object of the present invention to provide novel means for amplifying the movement of the thermally expansible member such that a certain amount of lost motion in the parts does not seriously affect the efficient operation of the device and the parts do not have to be made to quite such close limits, which, of course, is of great advantage in quantity production. The full significance of the foregoing statements will presently appear.

The thermostat illustrated is generally similar to that shown in my patent and comprises the usual elements 6 and 7, the one being non-expanding, or having a low co efficient of expansion, and the other being expansible, or having a comparatively high coeflicient of expansion. I prefer to make the element 6 of a rod of invar, which, as is well known, is practically free from expansion or contraction with changes in temperature, and prefer to make the element 7 of a brass or copper tube so as to expand and contract with temperature variations. The tube 7 is threaded or otherwise suitably fixed in a plug 8, a'hollow extension 9 of which is internally threaded to receive the externally threaded neck 10 of a cast hollow valve body 11. The rod 6 is adjustably secured at its outer end in the outer end of the tube 7 as by threading into a plug 12 which, in turn, is preferably soldered in the end of the tube 7. By virtue of this connection it will be evident that expansion and contraction of the tube 7 results in slight endwise movement of the rod 6. I provide a temperature adjustment by turning the rod 6 in the plug 12 to change the relation between the rod and the tube 7. The screw driver slot appearing at 13 provided in the plug 12 is used only in the assembling of the device. The adjustmentof the rod is made by swinging a lever 14 relative to a dial 15 graduated in any suitable manner, as, for example, Hot-Warm Gold. The plug 8 threads into a bushing 16, either in the side or bottom of the tank of a gas operated water heater, a portion of the wall of which appears at 17. The valve body 11 is connected between pipes 18 and 19, the former extending from the gas main and the latter being connected to the burner of the heater. A by-pass connection for a pilot light is provided for at 20. Flow of gas from the thermostat, the seat 22 being provided between the inlet and outlet ports 23 and 24 communicatin with the pipes 18 and 19, respectively. T e valve, as will presently ap pear, is arranged to be unseated under an impulse of the thermostat when the tubular element 7 thereof contracts a certain amount and causes corresponding'endwise movement of the rod element 6 to the right, the unseating of the valve being against the action of a coiled compression spring 25 which serves to seat the valve as soon as the thermostat allows that to happen, that being when the tubular element 7 has expanded to a sufficient extent to retract the rod 6 to the left a predetermined distance. The foregoing description will'sufiice for a general understanding of the device of my invention so that I may now proceed with the description of various novel features with which the invention is more particularly concerned.

According to the present invention I employ a normally convexo-concave spring metal diaphragm 26 which I prefer to call a clicker disk because of the fact that it is arranged to snap over dead center from the convexo-concave form, the snap-over action being accompanied by a clicking sound not particularly audible because of the fact that the disk is entirely enclosed in the body of the valve as the same is used herein. The distortion of the disk up to and slightly beyond the dead center is caused by the movement of the rod 6 above described. Since the movement of the rod, as stated before, is so sli ht, it is necessary to provide means for ampli eation thereof, this means in the present case consisting of a cylindrical plunger 27 and a pair of flat, resilient levers 28 disposed in the order named between the end of the rod 6 and one side of the disk 26. The plunger 27 is slidably received in the bore 29 of the neck 10 of the body 11 of the valve and is centrally counter-bored, as at 30, to provide a selfcentering seat for the beveled end 31 of the rod 6. The face of the plunger 27 presented to the levers 28 has a projecting annular knife-edged shoulder 32 arranged to have line contact with the levers near the outer ends. thereof, or, more specifically, at points on the circumference of a circle of a radius slightly less than that of the plunger. The levers 28 may be formed as separate pieces stamped from sheet metal, although, as a matter of facilitating assembling and making the positioning of the levers in the device more accurate, I prefer to stamp the same from a single piece with the outer ends of the levers connected by a ring 28. The extreme outer ends of the levers bear against an annular beveled shoulder 33 defining a slight reduction in diameter of the bore 29 of the neck 10. Since the levers are supported at their extreme outer ends and are borne against by the plug 27 at points near the outer ends, it will be evident that the levers will have rocking motion communicated thereto 'in the movement of the rod 6. The inner ends of the levers rest againstthe disk. 26 at the center thereof and are arranged to apply pressure at that point sufiicient to cause the disk to snap overdead center' to concavo-convex form. The stem 34 of the valve 21, or for that matter any other partwhich it is desired to operate, is arran ed to be operated from the center of the ot er side of the disk. The disk 26, it will be observed, rests freely at its outer edges on a beveled annular shoulder defining a still further reduction in diameter of the bore 29 of the neck 10. The fact that the annular shoulder 33 on which the levers 28 rest is ap reciably larger in diameter than the annu ar shoulder 35 enables me to use longer levers 28 and to securevproportionately greater amplification of the movement of the rod- 6;.in other words, the fact that I may use a disk of relatively small diameter does not impose a restriction on the amount of amplificatiorn In operation, assuming that the valve 21 is closed, when the tubular element 7 of the thermostat contracts, the rod element 6 moves slowly inwardly and causes the plunger 27 to apply pressure onto the levers 28 near the outer ends thereof. The levers 28, being resilient, flex more and more the farther the plunger 27 is moved inwardly, until they exert sufiicient pressure at the center of the diaphragm disk 26 to snap the same over dead center from the normally convexo-concaveform to concavo-convex form. Now, the diaphragm disk is peculiar in that it takes a m ch greater pressure to force the same over ead center to the concavo-convex form that it does to keep it from snapping back to its normal shape. Because of that, the levers 28, after they have snapped the disk past dead center, serve to hold the same against snapping back, the levers resting still in contact with the disk at the center thereof and still exerting a slight pressure thereon,

back assisted by the spring 25. Here again the resilience of the levers 28 is a factor in the operation; the levers are flexed slightly on the snap-back of thedisk, just enough to allow the disk to have the necessary amount of movement. If the levers 28 were not resilient it will be seen that the disk could only be snapped over dead center but could not time during cold weather the extreme movement-of the plunger 27 resulting from the extreme degree of contraction of the tubular element 7 of the thermostat might easily result in dama e to the diaphragm if it were not for the act that the levers-28 are resilient and arranged to yield. Because of the importance of the resilience, it is found that in the manufacture of these thermostats that it is very important to see to it that the sheet metal stock from which these levers are made does not vary too much in thickness, it being obvious that an increase in thickness would necessarily mean diminishing the resilience, everything else being equal, and vice versa in the case ofa decreasein thickness.

Before proceeding to a description of certain other novel features of the present invention, attention may be called to Fig. 4: showing a modification of the invention for use with oven regulators or other devices of a similar type where the snap-over action above described is not desired or required; instead of having the gas turned on and off abruptly, the flow is arranged/to be regulated to maintain some predetermined constant temperature for which the thermostat is set.

In this case, the clicker disk 26 is omitted and the levers 28 are arranged to bear directly against the end of the valve stem 3 or other part to be operated. The same amplification as secured in the form shown in ig. 3 by the cooperation of the plunger 27 and levers 28 is secured in this form so that for any finevariation in length of the expansible element 7 of the thermostat, reflected in a corresponding small movement of the rod 6, the valve 21, or other part associated with the stem 34, will be given a proportionate but amplified movement. Referring again to Figs. 1-3, and more particularly Fig. 1, it will be observed that the valve stem 34 is slidably received in a guide opening in a plu 36 having a press fit in the bore of the valve loody 11. A graphiteasbestos washer 37 is disposed in a recess in the plug 36 and fits snugly about the valve stem 34 for a gas-tight joint. A metallic washer 38 suitably having a drive fit in the same recess serves to hold the washer 37 in place. This kind of construction is prefersuch that the valve 21 may be operated precisely as desired; one valve can be made to operate exactly like another desplte slight mechanical variations such as are bound to creep in where these devices are made in quantity production. Ihe screw adjustment is a simple remedy for either extreme condition, that is, if the valve stem happens to be too long, in which case the gas would commence to flow slowly before the valve is snapped open, the stem :an be shortened, whereas if the valve stem happens to be too short, in which case the flow of gas would graduall be restricted before the valve is closed, t e stem can be lengthened, as required. If desired, the screw 39 may be made tose'rve still another purpose, namely, that of enabling extension of the stem 34 where a device 1s converted from the form shown'in Fig. 3 to that shown in Fig. 4 by the removal of the clicker disk 26, it being evident upon comparison of the two figures that the stem 34 will have to be lengthened appreciably to make up for the omission of the clicker disk.

I prefer to provide the head of the valve 21 as aseparate disk slidably received on the reduced end 40 of the valve stem 34 and to employ another graphite-asbestos washer 41 and metallic washer 42 to seal the joint between the head and the stem, the head seating against an annular shoulder 43 afforded at the inner end of the reduced portion 40 under the act-ion of the compression spring 25. The latter, in addition to tending normally to hold the valve seated, serves to hold the packing washer 41 with the washer 42 in proper posltion to seal the joint between the head and stem. The fact that the head is not rigid with the stem and is yieldingly urged to its seat avoids the likelihood of leakage when the valve is closed; the head of the valve takes its own seat so that it does not matter particularly if the stem 34 is not disposed precisely at right angles to the plane of the seat. The reduced end 40 of the valve stem has a-sliding fit in a bore 44 provided in a plug 45 threading into the valve body 11. An enlargement of the bore 44 receives the spring 25, as shown. A tubular screen 46 seated at one end on an annular shoulder 47 about the valve seat 22 and at the other end in an annular groove 48 formed on the inside of the plug 45, constitutes a complete enclosure for the valve 21'such that there is substantially no restriction imposed on thefiow of gas and still the desired protection is af- Furthermore, all of the parts can be produced at extremely low cost and can be assembled with considerable ease and facility,

7 such that the ultimate cost of the device 15 brought proportionately lower.

In Fig, 5, I have shown a still -further mo. fication of the invention wherein, instead 0 using the plunger 27 and rocking levers 28, a single lever 28" is employed in connection with the clicker disk 26. The lever 28" is pivoted at 50 and has the end of the rod 6 bearing against the same close to the pivot point to communicate rocking motion to the lever in the event of contraction of the tubular element 7 of the thermostat. It will be evident that substantially the same amount of amplification can be secured with a device constructed along these lines as with that shown in Fig. 1, also that the disk 26 may be omitted, as shown in Fig. 4, so as to adapt the device to operation as an oven regulator movement of the rod 6 being amplified a communicated directly to the valve stem 34, as previously described. In this form, as in the other forms, temperature adjustment may be made by swinging the lever 14 with reference to a dial at 15 so as to change the relation between the rod 6 and tube 7 of the thermostat, as previously described.

It is believed the foregoing description conveys a clear understanding of the objects and advantages of my invention. While I have illustrated and described the application thereof in the case of gas operated water heaters and in the case of oven regulators, it should be understood that there are numerous other possible applications. All legitimate modifications and adaptations of my invention are therefore to be construed as coming within the spirit and scope of the appended claims.

I claim: 7

1. In a thermostatic device of the character described, the combination with a thermostatic element arranged to move according to temperature variations and a valveor other element arranged to be operated, of means between said element and said valve for communicating amplified, abrupt movement from the former to the latter, said means comprising a normally conveXo-concave disk of spring material supported about the edges thereof so as to permit distortion thereof toward and past a dead center condition whereby the disk is arranged to snap-over to concavo-convex form, the said valve being arranged to have movement communicated thereto from the approximate center of the disk, one or more resilient levers bearing at one end against the center of the disk to distort the same and extending radially outwardly relative to tlie disk and pivotally supported at the other remote end, and a. part Ill , moving with the thermostatic element and hearing against the levers near the pivoted ends thereof.

2. A device as set forth in claim 1 wherein the valve has the stem thereof extending to the disk for operation directly thereby, and including a part adjustably threaded on the end of said stein for adjustment toward or away from the disk, for the purpose described.

3. In a thermostatic device of the character described, the combination with a thermostatic element arranged to move according to 1 temperature variations, and a valve or other element substantially concentric therewith arranged to be operated, of a body member, a plunger guided for movement with the thermostatic element in said body member, and-a plurality of lovers of equal length pivotally supported in said body at their outer ends and having the inner ends disposed end to end and arranged to operate said valve, said plunger having engagement with said levers near the outer ends thereof whereby in the movement of said element amplified movement is communicated to said valve.'

4. A device as set forth in claim 3 including an annulus interconnecting the levers preferably at their outer ends and holding the same in their proper positions relative to one another and relative to the plunger and valve. 5. In a thermostatic device of the character described, the combination with a thermostatic element arranged to move according to temperature variations, and a valve or other element substantially concentric therewith arranged to be operated, of a body member, a plunger guided for movement with the thermostatic element in said body member, a spring metal diaphragm disk disposed substantially concentric with the valve so as to communicate movement thereto from its approximate center, said disk being supported about the edges thereof, and one or more resilient levers between the plunger and the disk extending substantially radially relative to the latter and bearing against the saint at its approximate center at their inner ends and pivotally supported at their remote outer ends, said plunger having engagement with said levers near their outer ends. g 6. A thermostatic device of the character described comprising, in combination, a body member, a thermostat having an element arranged to have movement communicated thereto in the event of temperature variation, said body member having a cylindrical bore reduced at one point to provide an "annular shoulder of one radius and still further reduced at another point to provide another annular shoulder of a smaller radius, a clicker disk resting freely at its outer edges on the last mentioned annular shoulder, one or more leversrestingat their outer ends on the other shoulder and having the inner ends engaging the disk approximately centrally thereof, a lunger slidably received in the bore in bac of said levers and having enga ement with the levers near the. outer ends thereof, means providing an operating connection between said plunger and the movable element of the thermostat, and a part to be operated, such as a valve,in the ody member normally spring pressed to move in one direction, said valve having a part operated by the clicker disk at the approximate center of the latter.

7. In a device as set forth in claim 6, wherein the thermostat comprises a tube fixed with respect to the body member and a rod threadedly engaged at its outer end in the outer end of said tube and extending to the body member and constituting the movable element of the thermostat, means for manually adjusting the thermostat comprising a lever fixed to the rod and extending substantially radially therefrom to permit turning the same, the outer end of said lever being movable preferably with respect to a temperature scale.

8. A device as set forth in claim 6 wherein the part of the valve arranged to be 0 erated b the clicker disk has a screw ad ustably t readed therein to advance or-retard contact with the disk.

9. A thermostatic device of the character described comprising in combination a body member, a thermostat comprising a movable elementarranged to have movement in the event of temperature variation, said body member having a cylindrical bore reduced at one point to rovide an annular shoulder, a plunger slida 1y received in said bore, means providing an operating connection between said plunger and the movable element of the thermostat, one or more levers resting at their outer ends on said annular shoulder and extending inwardly to the approximate center of the bore, said plunger having engagement with said'levers near the outer ends thereof, and a part to be operated, such as a valve, 'in the body member normally spring ressed for movement in one direction, sai valve having a part extending toward said levers for operation thereby.

10. A device as set forth in claim 9 including a screw adjustably threaded in the part of the valve arranged to be operated by the levers, the adjustment of said screw servin to advance or retard the operation of the va ve.

11. In a device of the character described comprising a valve body member having a valve seat therein between an inlet and an outlet port, and a valve coo crating therewith, a plug disposed substantia ly concentric with the valve seat and closing an opening in the valve body member through which the valve is arranged to be inserted into said body, and a tubular screen in said body between the inlet and outlet enclosing the valve and valve seat and held in place by said plug, one

end of said screen fittin on an annular shoulder provided in sai bod about the valve seat and the other end 0 said screen fiilbting in an annular groove provided in said u p 1%. A thermostatic device of the character described comprising in combination, a plug member having a thermostat mounted thereon with the movable element of said thermostat extending through an opening in said plug, said plug having a hollow extension about the projecting end of said element,'a valve body member mounted on said extension in juxtaposition to the end of said element, a valve in said body normally held inone position by spring pressure, and means having an operative connection with the end of said element arranged in the movement thereof to communicate amplified movement to said valve against the action of its spring means, said means comprising a plunger slidably mounted in the valve body member and having the movable element engaging the same centrally thereof, one or more levers resting at their outer ends on a shoulder in said body and engaged by the plunger near the outer ends thereof, the inner ends of said levers being arranged to have amplified movement for any given movement of the plunger and being arranged to communicate the amplified movement to the valve.

13. A thermostatic device of the character described comprising in combination, a plug member having a thermostat mounted thereon with the movable element of said thermostat extending through an' opening in said plug, said plug having a hollow extension about the projecting end of said element, a valve body member mounted on said extension in juxtaposition to the end of said element, a valve in said body normally held in one position by spring pressure, and means having an operative connection with the end of said element arranged in the movement thereof to communicate amplified movement to said valve against the action of its spring means, said means comprising a plunger slidably mounted in the valve body member and having the movable element engaging the same centrally thereof, one or more levers resting at their outer ends on a shoulder in said body and engaged by the plunger near the outer ends thereof, the inner ends of said levers being arranged to have amplified movement for any given movement of the plunger, and a clicker disk resting at its outer edges on another shoulder in the body member and having the inner ends of said levers engaging one side thereof approximately centrally, said disk being arranged to communicate movement to the valve from the other side thereof.

14. A thermostatic device as set forth in claim'9 wherein two levers are employed extending in diametrically opposite directions so as to rest on the annular shoulder at diametrically opposite points thereof, said levers being interconnected by a ring portion also adapted to rest on said annular shoulder, said ring portion serving to hold the levers together for assembly as a unit.

15. Athermostatic device of the character described comprising, in combination, a body member, a thermostat associated therewith having an element arranged to have movement communicated thereto in the event of temperature variation, a diaphragm disk of spring material supported about the edges thereof in said body, a plunger guided for axial movement toward and away from the disk, a valve or other element arranged to be operated from the back of the disk from the approximate center thereof, and one or more levers supported at their outer ends for pivotal movement between the plunger and the disk, said levers engaging the disk at the central portion thereof, and the plunger having engagement with the levers near the outer ends thereof.

"16. A device as set forth in claim 15 wherein the disk is normally convexo-concave and is arranged to be snapped over dead center to concavo-convex form, and wherein the levers are resilient so as to flex under pressure exerted thereon by the plunger until loaded suliiciently to snap the disk over dead center, the said disk being arranged in snapping back to flex the levers slightly.

17. A thermostatic device of the character described comprising, in combination, a body member, a thermostat associated therewith having an element arranged to have movement communicated thereto in the event of. temperature variation, a diaphragm disk of spring material supported about the edges thereof in said body, a plunger guided for axial movement toward and away from the disk, a valve or other element arranged to be operated from the back of the disk from the approximate center thereof, and resilient means between the plunger and the disk operating against the central portion of the latter and arranged to be flexed by the plunger until loaded sufficiently to snap said disk over dead center.

18. A thermostatic device of the character described comprising, in combination, a body member, a thermostat associated therewith having an element arranged to have movement communicated thereto in the event of temperature variation, a diaphragm disk of spring material normally convexo-concave in form but arranged to be snapped over dead center to concavo-convex form, said disk beingsupported about the edges thereof in said body, a valve or other element arranged to be operated from the back of the disk from the approximate center thereof and movement amplifying means between the movable thermostatic element and the front of the member, a thermostat associated therewit having an element arranged to have movement' communicated thereto in the event of temperature variation, a diaphragm disk of spring material of a certain diameter sup ported about the edges thereof in said body,

a plunger guided for axial movement toward and away from the disk, a valve or other element arranged to be operated from the back of the disk from the approximate center thereof, and one or more levers supported at their outer ends for pivotal movement between the plunger and the disk, the said.

levers being longer than the radius of said disk and extending beyond the outer edges thereof, and the plunger having engagement with the levers near the outer ends thereof.

20. A device as set forth in claim 19 wherein the disk is normally convexo-concave in form and is arranged to be snapped over dead center to concavo-convex form and is mounted in said body so that the marginal edge there of is loosely supported and radial expansion of said disk under pressure is permitted.

21. A device as set forth in claim 19 wherein the disk is normally of a convexoconcave form and comparatively small in diameter but mounted in said body so that the marginal edge thereof is loosely supported, and radial expansion of said disk under pressure is permitted, and wherein said levers for operating the same are resilient and arranged to be flexed until loaded sufficiently to snap the disk over dead center,

the said disk in snapping back being arranged to flex said levers slightly.

22. A device as set forth in claim 15 including anannulus connected with the outer ends of said levers and serving to hold the same in a predetermined operative relation to the plunger and disk.

23. A device as set forth in claim 1 including an annulus connected with said levers preferably at their pivoted ends for holding the same in proper operative relation with respect to the disk.

24. A device as set forth in claim 5 including an annulus connected with said levers preferably at their pivoted ends for holding the same in proper operative relation with respect to the disk and plunger.

25. A device as set forth in claim 6 including an annulus interconnecting the outer 'ends of said levers and resting on the same shoulder therewith and serving to: hold said levers in a predetermined relation to one another and in proper operative relation with respect to theclicker disk and plunger.

26. A device as set forth in claim 9 including an annulus connected with the one or more levers at their outer ends for holding the outer ends of said levers in proper relation to the annular shoulder on which the same are arranged to rest, and thus maintain the proper relation between the levers and the plunger cooperating therewith as well as the valve operated thereby.

27. A thermostatic device of the character described comprising in combination, a plug member having a thermostat mounted thereon with the movable element of said thermostat extending through an opening in said plug, said plug having a hollow extension about the projecting end of said element, a valve body member mounted on said extension in juxtaposition to the end of said element, a

valve in said body normally held in one position by spring pressure, and means having an operative connection with the end of said element arranged in the movement thereof to communicate amplified movement to said valve against the action of its spring means,

said means comprising a plunger slidably mounted in the valve body member and having the movable element engaging the same centrally thereof, one or more levers resting at their outer ends on a shoulder in said body and engaged by the plunger near the outer ends thereof, means arranged to fit on the same shoulder with the levers arranged to hold the same in proper position with respect to the shoulder and the plunger, the inner ends of said levers being arranged to have amplified movement for any given movement of the plunger and being arranged to communicate the amplified movement to the valve.

28. A thermostatic device of the character described comprising in combination, a plug member having a thermostat mounted thereon with the movable element of saidthermostat extending through an opening in said plug, said plug having a hollow extension about the projecting end of said element, a valve body member mounted on said extension in juxtaposition to the end of said element, avalve in said body normally held in one position by spring pressure, and

ment thereof to communicate amplified movement to said valve against the action of its spring means, said means comprising a plung er slidably mounted in the valve body member and having the movable element engaging the same centrally thereof, one or more levers resting at theirouter ends-p11. a shoulder in said body and engaged by the plunger near the outer ends thereof, means arranged to fit on the same shoulder with the levers arranged to hold the same in proper position with respect to the shoulder and the plunger, the inner ends of said levers being arranged to have amplified movement for any given movement of the plunger, and a clicker disk resting at its outer edges on another shoulder in the bod member and having the inner ends of sai levers engaging one side thereof approximately centrally, said disk being ari ranged to communicate movement to the valve from the other side thereof.

In witness of the foregoing I affix my signature.

JOHN H. GRAYSON. 

